Buggy code:
public class ValueMap extends LinkedHashMap < String , Object > implements IValueMap { public static final ValueMap EMPTY_MAP ; private static final long serialVersionUID = 1L ; private boolean immutable = false ; public ValueMap ( ) { } public ValueMap ( final Map < ? extends String , ? extends Object > map ) { } public ValueMap ( final String keyValuePairs ) { } public ValueMap ( final String keyValuePairs , final String delimiter ) { } public ValueMap ( final String keyValuePairs , final String delimiter , final MetaPattern valuePattern ) { } @ Override public final void clear ( ) { } public final boolean getBoolean ( final String key ) throws StringValueConversionException { } public final double getDouble ( final String key ) throws StringValueConversionException { } public final double getDouble ( final String key , final double defaultValue ) throws StringValueConversionException { } public final Duration getDuration ( final String key ) throws StringValueConversionException { } public final int getInt ( final String key ) throws StringValueConversionException { } public final int getInt ( final String key , final int defaultValue ) throws StringValueConversionException { } public final long getLong ( final String key ) throws StringValueConversionException { } public final long getLong ( final String key , final long defaultValue ) throws StringValueConversionException { } public final String getString ( final String key , final String defaultValue ) { } public final String getString ( final String key ) { } public final CharSequence getCharSequence ( final String key ) { } public String [ ] getStringArray ( final String key ) { } public StringValue getStringValue ( final String key ) { } public final Time getTime ( final String key ) throws StringValueConversionException { } public final boolean isImmutable ( ) { } public final IValueMap makeImmutable ( ) { } @ Override public Object put ( final String key , final Object value ) { } public final Object add ( final String key , final String value ) { } @ Override public void putAll ( final Map < ? extends String , ? extends Object > map ) { } @ Override public Object remove ( final Object key ) { } public String getKey ( final String key ) { } @ Override public String toString ( ) { <START_BUG> final StringBuffer buffer = new StringBuffer ( ) ; <END_BUG> boolean first = true ; for ( Map . Entry < String , Object > entry : entrySet ( ) ) { if ( first == false ) { buffer . append ( '<seq2seq4repair_space>' ) ; } first = false ; buffer . append ( entry . getKey ( ) ) ; buffer . append ( "<seq2seq4repair_space>=<seq2seq4repair_space>\"" ) ; final Object value = entry . getValue ( ) ; if ( value == null ) { buffer . append ( "null" ) ; } else if ( value . getClass ( ) . isArray ( ) ) { buffer . append ( Arrays . asList ( ( ( Object [ ] ) ( value ) ) ) ) ; } else { buffer . append ( value ) ; } buffer . append ( '\"' ) ; } return buffer . toString ( ) ; } private void checkMutability ( ) { } public Boolean getAsBoolean ( String key ) { } public boolean getAsBoolean ( String key , boolean defaultValue ) { } public Integer getAsInteger ( String key ) { } public int getAsInteger ( String key , int defaultValue ) { } public Long getAsLong ( String key ) { } public long getAsLong ( String key , long defaultValue ) { } public Double getAsDouble ( String key ) { } public double getAsDouble ( final String key , final double defaultValue ) { } public Duration getAsDuration ( final String key ) { } public Duration getAsDuration ( final String key , final Duration defaultValue ) { } public Time getAsTime ( final String key ) { } public Time getAsTime ( final String key , final Time defaultValue ) { } public < T extends Enum < T > > T getAsEnum ( final String key , final Class < T > eClass ) { } public < T extends Enum < T > > T getAsEnum ( final String key , final T defaultValue ) { } public < T extends Enum < T > > T getAsEnum ( final String key , final Class < T > eClass , final T defaultValue ) { } @ SuppressWarnings ( { "unchecked" } ) private < T extends Enum < T > > T getEnumImpl ( final String key , final Class < ? > eClass , final T defaultValue ) { } }

Fix:
final StringBuilder buffer = new StringBuilder ( ) ;